The practice for producing the thin film using sputtering phenomenon and processing the thin film for application to the device has been widely implemented in the industry. The sputtering phenomenon is caused by making high energy ion incident onto the target from which sputter particles (neutral particles) are generated, so that the sputter particles are deposited on the substrate.
Generally, the sputtering film forming apparatus is provided with a shield called shutter capable of opening and closing between the target and the substrate. The shutter is used to control the timing for starting the film formation so as not to start the film forming process until stabilization of the plasma state within the vacuum vessel. Specifically, the shutter is kept closed until stabilization of the plasma generated upon application of high voltage to the target so that no film is formed on the substrate. Upon stabilization of the plasma, the shutter is opened to start the film formation. Controlling start of the film formation using the shutter makes it possible to conduct well controlled film formation on the substrate with stabilized plasma, resulting in the film with high quality.
Patent Document 1 discloses the high frequency sputtering apparatus and method capable of forming the thin film with excellent reproducibility with respect to the film quality and film thickness by opening the shutter disposed between the substrate and the target upon stabilization of self bias while detecting the self bias voltage induced in the target. Patent Document 2 discloses the sputtering apparatus having the sputter cathode provided with a tubular cathode cover which surrounds the side of the sputter surface, and the shutter that can be opened and closed provided in the open end portion of the cathode cover. The sputtering apparatus disclosed in Patent Document 2 is capable of reducing turnaround of the sputter particles upon discharge in the state where the shutter is closed before starting the film formation such as the target cleaning.